The present invention relates to an arrangement for measuring diffusing particles. More particularly, it relates to an arrangement for measuring diffusing particles, which has at least one monochromatic radiation source and a light measuring device as well as at least one material-limited indicator chamber which is permeable by particles to be measured and is provided with an optical fluorescence indicator which is optically changeable by the particles.
Arrangements of the above-mentioned general type are known in the art. The known arrangements are used for example for measurements of blood component oxygen and its partial pressure pO.sub.2 or carbon dioxide and its partial pressure pCO.sub.2 invasibly or noninvasibly. For this purpose the indicator chamber which is permeable by the particles to be measured, known shortly as optode, is brought into operative communication with the object to be measured and the change in the measuring light is measured by the optode. One of such arrangements is disclosed, for example, in the U.S. Pat. No. 3,769,961. In the arrangement in accordance with this patent the electrodes which are arranged on a contact lens formed as an electrode carrier measure blood components, such as for example oxygen or carbon dioxide on an eyelid.
In this manner a noninvasive measurement of these blood components is possible, since on the lid mucous membrane or the conjunctiva these blood components have approximately arterial value, or differ from it only by a constant factor.
The electrodes which in the known arrangement are used for measurements have as all electrodes an aging and must be frequently subjected to observations with considerable cost. Moreover, the wire lines for the electrodes must be guided on the contact lens that leads to undesirably affecting of the patients. Furthermore, the miniaturization of electrodes is possible only to a limited extent. Also, other particle types such as for example metabolism products from the metabolism of the eye or other particles such as for example cations or anions lie at this measuring location. They cannot, however, be measured since there are no suitable sensors.